226 lines
		
	
	
		
			6.7 KiB
		
	
	
	
		
			LLVM
		
	
	
	
			
		
		
	
	
			226 lines
		
	
	
		
			6.7 KiB
		
	
	
	
		
			LLVM
		
	
	
	
| ; RUN: llc -mtriple=armv4t-eabi %s -o - | FileCheck %s --check-prefix=CHECK --check-prefix=V4T
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| ; RUN: llc -mtriple=armv6t2-eabi %s -o - | FileCheck %s --check-prefix=CHECK --check-prefix=V6T2
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| 
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| ; Check for several conditions that should result in SSAT.
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| ; For example, the base test is equivalent to
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| ; x < -k ? -k : (x > k ? k : x) in C. All patterns that bound x
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| ; to the interval [-k, k] where k is a power of 2 can be
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| ; transformed into SSAT. At the end there are some tests
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| ; checking that conditionals are not transformed if they don't
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| ; match the right pattern.
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| 
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| ;
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| ; Base tests with different bit widths
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| ;
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| 
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| ; x < -k ? -k : (x > k ? k : x)
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| ; 32-bit base test
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| define i32 @sat_base_32bit(i32 %x) #0 {
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| ; CHECK-LABEL: sat_base_32bit:
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| ; V6T2: ssat r0, #24, r0
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| ; V4T-NOT: ssat
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| entry:
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|   %cmpLow = icmp slt i32 %x, -8388608
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|   %cmpUp = icmp sgt i32 %x, 8388607
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|   %saturateUp = select i1 %cmpUp, i32 8388607, i32 %x
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|   %saturateLow = select i1 %cmpLow, i32 -8388608, i32 %saturateUp
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|   ret i32 %saturateLow
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| }
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| 
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| ; x < -k ? -k : (x > k ? k : x)
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| ; 16-bit base test
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| define i16 @sat_base_16bit(i16 %x) #0 {
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| ; CHECK-LABEL: sat_base_16bit:
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| ; V6T2: ssat r0, #12, r0
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| ; V4T-NOT: ssat
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| entry:
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|   %cmpLow = icmp slt i16 %x, -2048
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|   %cmpUp = icmp sgt i16 %x, 2047
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|   %saturateUp = select i1 %cmpUp, i16 2047, i16 %x
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|   %saturateLow = select i1 %cmpLow, i16 -2048, i16 %saturateUp
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|   ret i16 %saturateLow
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| }
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| 
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| ; x < -k ? -k : (x > k ? k : x)
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| ; 8-bit base test
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| define i8 @sat_base_8bit(i8 %x) #0 {
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| ; CHECK-LABEL: sat_base_8bit:
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| ; V6T2: ssat r0, #6, r0
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| ; V4T-NOT: ssat
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| entry:
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|   %cmpLow = icmp slt i8 %x, -32
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|   %cmpUp = icmp sgt i8 %x, 31
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|   %saturateUp = select i1 %cmpUp, i8 31, i8 %x
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|   %saturateLow = select i1 %cmpLow, i8 -32, i8 %saturateUp
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|   ret i8 %saturateLow
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| }
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| 
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| ;
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| ; Tests where the conditionals that check for upper and lower bounds,
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| ; or the < and > operators, are arranged in different ways. Only some
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| ; of the possible combinations that lead to SSAT are tested.
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| ;
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| 
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| ; x < -k ? -k : (x < k ? x : k)
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| define i32 @sat_lower_upper_1(i32 %x) #0 {
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| ; CHECK-LABEL: sat_lower_upper_1:
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| ; V6T2: ssat r0, #24, r0
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| ; V4T-NOT: ssat
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| entry:
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|   %cmpLow = icmp slt i32 %x, -8388608
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|   %cmpUp = icmp slt i32 %x, 8388607
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|   %saturateUp = select i1 %cmpUp, i32 %x, i32 8388607
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|   %saturateLow = select i1 %cmpLow, i32 -8388608, i32 %saturateUp
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|   ret i32 %saturateLow
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| }
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| 
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| ; x > -k ? (x > k ? k : x) : -k
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| define i32 @sat_lower_upper_2(i32 %x) #0 {
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| ; CHECK-LABEL: sat_lower_upper_2:
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| ; V6T2: ssat    r0, #24, r0
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| ; V4T-NOT: ssat
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| entry:
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|   %cmpLow = icmp sgt i32 %x, -8388608
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|   %cmpUp = icmp sgt i32 %x, 8388607
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|   %saturateUp = select i1 %cmpUp, i32 8388607, i32 %x
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|   %saturateLow = select i1 %cmpLow, i32 %saturateUp, i32 -8388608
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|   ret i32 %saturateLow
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| }
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| 
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| ; x < k ? (x < -k ? -k : x) : k
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| define i32 @sat_upper_lower_1(i32 %x) #0 {
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| ; CHECK-LABEL: sat_upper_lower_1:
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| ; V6T2: ssat    r0, #24, r0
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| ; V4T-NOT: ssat
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| entry:
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|   %cmpUp = icmp slt i32 %x, 8388607
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|   %cmpLow = icmp slt i32 %x, -8388608
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|   %saturateLow = select i1 %cmpLow, i32 -8388608, i32 %x
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|   %saturateUp = select i1 %cmpUp, i32 %saturateLow, i32 8388607
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|   ret i32 %saturateUp
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| }
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| 
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| ; x > k ? k : (x < -k ? -k : x)
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| define i32 @sat_upper_lower_2(i32 %x) #0 {
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| ; CHECK-LABEL: sat_upper_lower_2:
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| ; V6T2: ssat    r0, #24, r0
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| ; V4T-NOT: ssat
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| entry:
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|   %cmpUp = icmp sgt i32 %x, 8388607
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|   %cmpLow = icmp slt i32 %x, -8388608
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|   %saturateLow = select i1 %cmpLow, i32 -8388608, i32 %x
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|   %saturateUp = select i1 %cmpUp, i32 8388607, i32 %saturateLow
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|   ret i32 %saturateUp
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| }
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| 
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| ; k < x ? k : (x > -k ? x : -k)
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| define i32 @sat_upper_lower_3(i32 %x) #0 {
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| ; CHECK-LABEL: sat_upper_lower_3:
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| ; V6T2: ssat    r0, #24, r0
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| ; V4T-NOT: ssat
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| entry:
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|   %cmpUp = icmp slt i32 8388607, %x
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|   %cmpLow = icmp sgt i32 %x, -8388608
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|   %saturateLow = select i1 %cmpLow, i32 %x, i32 -8388608
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|   %saturateUp = select i1 %cmpUp, i32 8388607, i32 %saturateLow
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|   ret i32 %saturateUp
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| }
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| 
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| ;
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| ; Miscellanea
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| ;
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| 
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| ; Check that >= and <= work the same as > and <
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| ; k <= x ? k : (x >= -k ? x : -k)
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| define i32 @sat_le_ge(i32 %x) #0 {
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| ; CHECK-LABEL: sat_le_ge:
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| ; V6T2: ssat    r0, #24, r0
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| ; V4T-NOT: ssat
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| entry:
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|   %cmpUp = icmp sle i32 8388607, %x
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|   %cmpLow = icmp sge i32 %x, -8388608
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|   %saturateLow = select i1 %cmpLow, i32 %x, i32 -8388608
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|   %saturateUp = select i1 %cmpUp, i32 8388607, i32 %saturateLow
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|   ret i32 %saturateUp
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| }
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| 
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| ;
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| ; The following tests check for patterns that should not transform
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| ; into SSAT but are similar enough that could confuse the selector.
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| ;
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| 
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| ; x > k ? k : (x > -k ? -k : x)
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| ; First condition upper-saturates, second doesn't lower-saturate.
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| define i32 @no_sat_missing_lower(i32 %x) #0 {
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| ; CHECK-LABEL: no_sat_missing_lower
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| ; CHECK-NOT: ssat
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| entry:
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|   %cmpUp = icmp sgt i32 %x, 8388607
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|   %cmpLow = icmp sgt i32 %x, -8388608
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|   %saturateLow = select i1 %cmpLow, i32 -8388608, i32 %x
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|   %saturateUp = select i1 %cmpUp, i32 8388607, i32 %saturateLow
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|   ret i32 %saturateUp
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| }
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| 
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| ; x < k ? k : (x < -k ? -k : x)
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| ; Second condition lower-saturates, first doesn't upper-saturate.
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| define i32 @no_sat_missing_upper(i32 %x) #0 {
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| ; CHECK-LABEL: no_sat_missing_upper:
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| ; CHECK-NOT: ssat
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| entry:
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|   %cmpUp = icmp slt i32 %x, 8388607
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|   %cmpLow = icmp slt i32 %x, -8388608
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|   %saturateLow = select i1 %cmpLow, i32 -8388608, i32 %x
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|   %saturateUp = select i1 %cmpUp, i32 8388607, i32 %saturateLow
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|   ret i32 %saturateUp
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| }
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| 
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| ; Lower constant is different in the select and in the compare
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| define i32 @no_sat_incorrect_constant(i32 %x) #0 {
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| ; CHECK-LABEL: no_sat_incorrect_constant:
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| ; CHECK-NOT: ssat
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| entry:
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|   %cmpUp = icmp sgt i32 %x, 8388607
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|   %cmpLow = icmp slt i32 %x, -8388608
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|   %saturateLow = select i1 %cmpLow, i32 -8388607, i32 %x
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|   %saturateUp = select i1 %cmpUp, i32 8388607, i32 %saturateLow
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|   ret i32 %saturateUp
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| }
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| 
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| ; The interval is not [k, ~k]
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| define i32 @no_sat_incorrect_interval(i32 %x) #0 {
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| ; CHECK-LABEL: no_sat_incorrect_interval:
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| ; CHECK-NOT: ssat
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| entry:
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|   %cmpUp = icmp sgt i32 %x, 8388607
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|   %cmpLow = icmp slt i32 %x, -19088744
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|   %saturateLow = select i1 %cmpLow, i32 -19088744, i32 %x
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|   %saturateUp = select i1 %cmpUp, i32 8388607, i32 %saturateLow
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|   ret i32 %saturateUp
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| }
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| 
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| ; The returned value (y) is not the same as the tested value (x).
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| define i32 @no_sat_incorrect_return(i32 %x, i32 %y) #0 {
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| ; CHECK-LABEL: no_sat_incorrect_return:
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| ; CHECK-NOT: ssat
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| entry:
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|   %cmpUp = icmp sgt i32 %x, 8388607
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|   %cmpLow = icmp slt i32 %x, -8388608
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|   %saturateLow = select i1 %cmpLow, i32 -8388608, i32 %y
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|   %saturateUp = select i1 %cmpUp, i32 8388607, i32 %saturateLow
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|   ret i32 %saturateUp
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| }
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| 
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| ; One of the values in a compare (y) is not the same as the rest
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| ; of the compare and select values (x).
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| define i32 @no_sat_incorrect_compare(i32 %x, i32 %y) #0 {
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| ; CHECK-LABEL: no_sat_incorrect_compare:
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| ; CHECK-NOT: ssat
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| entry:
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|   %cmpUp = icmp sgt i32 %x, 8388607
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|   %cmpLow = icmp slt i32 %y, -8388608
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|   %saturateLow = select i1 %cmpLow, i32 -8388608, i32 %x
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|   %saturateUp = select i1 %cmpUp, i32 8388607, i32 %saturateLow
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|   ret i32 %saturateUp
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| }
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