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Meera Nakrani fa71cd65a0 [ARM] Selects SSAT/USAT from correct LLVM IR
LLVM will canonicalize conditional selectors to a different pattern than the old code that was used.
This is updating the function to match the new expected patterns and select SSAT or USAT when successful.
Tests have also been updated to use the new patterns.

Differential Review: https://reviews.llvm.org/D87379
2020-09-14 10:58:21 +00:00

226 lines
6.6 KiB
LLVM

; RUN: llc -mtriple=armv4t-eabi %s -o - | FileCheck %s --check-prefix=CHECK --check-prefix=V4T
; RUN: llc -mtriple=armv6t2-eabi %s -o - | FileCheck %s --check-prefix=CHECK --check-prefix=V6T2
; Check for several conditions that should result in SSAT.
; For example, the base test is equivalent to
; x < -k ? -k : (x > k ? k : x) in C. All patterns that bound x
; to the interval [-k, k] where k is a power of 2 can be
; transformed into SSAT. At the end there are some tests
; checking that conditionals are not transformed if they don't
; match the right pattern.
;
; Base tests with different bit widths
;
; x < -k ? -k : (x > k ? k : x)
; 32-bit base test
define i32 @sat_base_32bit(i32 %x) #0 {
; CHECK-LABEL: sat_base_32bit:
; V6T2: ssat r0, #24, r0
; V4T-NOT: ssat
entry:
%0 = icmp slt i32 %x, 8388607
%saturateUp = select i1 %0, i32 %x, i32 8388607
%1 = icmp sgt i32 %saturateUp, -8388608
%saturateLow = select i1 %1, i32 %saturateUp, i32 -8388608
ret i32 %saturateLow
}
; x < -k ? -k : (x > k ? k : x)
; 16-bit base test
define i16 @sat_base_16bit(i16 %x) #0 {
; CHECK-LABEL: sat_base_16bit:
; V6T2: ssat r0, #12, r0
; V4T-NOT: ssat
entry:
%0 = icmp slt i16 %x, 2047
%saturateUp = select i1 %0, i16 %x, i16 2047
%1 = icmp sgt i16 %saturateUp, -2048
%saturateLow = select i1 %1, i16 %saturateUp, i16 -2048
ret i16 %saturateLow
}
; x < -k ? -k : (x > k ? k : x)
; 8-bit base test
define i8 @sat_base_8bit(i8 %x) #0 {
; CHECK-LABEL: sat_base_8bit:
; V6T2: ssat r0, #6, r0
; V4T-NOT: ssat
entry:
%0 = icmp slt i8 %x, 31
%saturateUp = select i1 %0, i8 %x, i8 31
%1 = icmp sgt i8 %saturateUp, -32
%saturateLow = select i1 %1, i8 %saturateUp, i8 -32
ret i8 %saturateLow
}
;
; Tests where the conditionals that check for upper and lower bounds,
; or the < and > operators, are arranged in different ways. Only some
; of the possible combinations that lead to SSAT are tested.
;
; x < -k ? -k : (x < k ? x : k)
define i32 @sat_lower_upper_1(i32 %x) #0 {
; CHECK-LABEL: sat_lower_upper_1:
; V6T2: ssat r0, #24, r0
; V4T-NOT: ssat
entry:
%cmpUp = icmp slt i32 %x, 8388607
%saturateUp = select i1 %cmpUp, i32 %x, i32 8388607
%0 = icmp sgt i32 %saturateUp, -8388608
%saturateLow = select i1 %0, i32 %saturateUp, i32 -8388608
ret i32 %saturateLow
}
; x > -k ? (x > k ? k : x) : -k
define i32 @sat_lower_upper_2(i32 %x) #0 {
; CHECK-LABEL: sat_lower_upper_2:
; V6T2: ssat r0, #24, r0
; V4T-NOT: ssat
entry:
%0 = icmp slt i32 %x, 8388607
%saturateUp = select i1 %0, i32 %x, i32 8388607
%1 = icmp sgt i32 %saturateUp, -8388608
%saturateLow = select i1 %1, i32 %saturateUp, i32 -8388608
ret i32 %saturateLow
}
; x < k ? (x < -k ? -k : x) : k
define i32 @sat_upper_lower_1(i32 %x) #0 {
; CHECK-LABEL: sat_upper_lower_1:
; V6T2: ssat r0, #24, r0
; V4T-NOT: ssat
entry:
%0 = icmp sgt i32 %x, -8388608
%saturateLow = select i1 %0, i32 %x, i32 -8388608
%1 = icmp slt i32 %saturateLow, 8388607
%saturateUp = select i1 %1, i32 %saturateLow, i32 8388607
ret i32 %saturateUp
}
; x > k ? k : (x < -k ? -k : x)
define i32 @sat_upper_lower_2(i32 %x) #0 {
; CHECK-LABEL: sat_upper_lower_2:
; V6T2: ssat r0, #24, r0
; V4T-NOT: ssat
entry:
%0 = icmp sgt i32 %x, -8388608
%saturateLow = select i1 %0, i32 %x, i32 -8388608
%1 = icmp slt i32 %saturateLow, 8388607
%saturateUp = select i1 %1, i32 %saturateLow, i32 8388607
ret i32 %saturateUp
}
; k < x ? k : (x > -k ? x : -k)
define i32 @sat_upper_lower_3(i32 %x) #0 {
; CHECK-LABEL: sat_upper_lower_3:
; V6T2: ssat r0, #24, r0
; V4T-NOT: ssat
entry:
%cmpLow = icmp sgt i32 %x, -8388608
%saturateLow = select i1 %cmpLow, i32 %x, i32 -8388608
%0 = icmp slt i32 %saturateLow, 8388607
%saturateUp = select i1 %0, i32 %saturateLow, i32 8388607
ret i32 %saturateUp
}
;
; Miscellanea
;
; Check that >= and <= work the same as > and <
; k <= x ? k : (x >= -k ? x : -k)
define i32 @sat_le_ge(i32 %x) #0 {
; CHECK-LABEL: sat_le_ge:
; V6T2: ssat r0, #24, r0
; V4T-NOT: ssat
entry:
%0 = icmp sgt i32 %x, -8388608
%saturateLow = select i1 %0, i32 %x, i32 -8388608
%1 = icmp slt i32 %saturateLow, 8388607
%saturateUp = select i1 %1, i32 %saturateLow, i32 8388607
ret i32 %saturateUp
}
;
; The following tests check for patterns that should not transform
; into SSAT but are similar enough that could confuse the selector.
;
; x > k ? k : (x > -k ? -k : x)
; First condition upper-saturates, second doesn't lower-saturate.
define i32 @no_sat_missing_lower(i32 %x) #0 {
; CHECK-LABEL: no_sat_missing_lower
; CHECK-NOT: ssat
entry:
%cmpUp = icmp sgt i32 %x, 8388607
%0 = icmp slt i32 %x, -8388608
%saturateLow = select i1 %0, i32 %x, i32 -8388608
%saturateUp = select i1 %cmpUp, i32 8388607, i32 %saturateLow
ret i32 %saturateUp
}
; x < k ? k : (x < -k ? -k : x)
; Second condition lower-saturates, first doesn't upper-saturate.
define i32 @no_sat_missing_upper(i32 %x) #0 {
; CHECK-LABEL: no_sat_missing_upper:
; CHECK-NOT: ssat
entry:
%cmpUp = icmp slt i32 %x, 8388607
%0 = icmp sgt i32 %x, -8388608
%saturateLow = select i1 %0, i32 %x, i32 -8388608
%saturateUp = select i1 %cmpUp, i32 8388607, i32 %saturateLow
ret i32 %saturateUp
}
; Lower constant is different in the select and in the compare
define i32 @no_sat_incorrect_constant(i32 %x) #0 {
; CHECK-LABEL: no_sat_incorrect_constant:
; CHECK-NOT: ssat
entry:
%cmpUp = icmp sgt i32 %x, 8388607
%cmpLow = icmp slt i32 %x, -8388608
%saturateLow = select i1 %cmpLow, i32 -8388607, i32 %x
%saturateUp = select i1 %cmpUp, i32 8388607, i32 %saturateLow
ret i32 %saturateUp
}
; The interval is not [k, ~k]
define i32 @no_sat_incorrect_interval(i32 %x) #0 {
; CHECK-LABEL: no_sat_incorrect_interval:
; CHECK-NOT: ssat
entry:
%0 = icmp sgt i32 %x, -19088744
%saturateLow = select i1 %0, i32 %x, i32 -19088744
%1 = icmp slt i32 %saturateLow, 8388607
%saturateUp = select i1 %1, i32 %saturateLow, i32 8388607
ret i32 %saturateUp
}
; The returned value (y) is not the same as the tested value (x).
define i32 @no_sat_incorrect_return(i32 %x, i32 %y) #0 {
; CHECK-LABEL: no_sat_incorrect_return:
; CHECK-NOT: ssat
entry:
%cmpUp = icmp sgt i32 %x, 8388607
%cmpLow = icmp slt i32 %x, -8388608
%saturateLow = select i1 %cmpLow, i32 -8388608, i32 %y
%saturateUp = select i1 %cmpUp, i32 8388607, i32 %saturateLow
ret i32 %saturateUp
}
; One of the values in a compare (y) is not the same as the rest
; of the compare and select values (x).
define i32 @no_sat_incorrect_compare(i32 %x, i32 %y) #0 {
; CHECK-LABEL: no_sat_incorrect_compare:
; CHECK-NOT: ssat
entry:
%cmpUp = icmp sgt i32 %x, 8388607
%cmpLow = icmp slt i32 %y, -8388608
%saturateLow = select i1 %cmpLow, i32 -8388608, i32 %x
%saturateUp = select i1 %cmpUp, i32 8388607, i32 %saturateLow
ret i32 %saturateUp
}