[llvm] e471fda - [InstCombine] known-phi-br.ll - add multiuse of compare results to avoid predicate inverse and add negative tests

Simon Pilgrim via llvm-commits llvm-commits at lists.llvm.org
Mon Aug 15 09:59:38 PDT 2022


Author: Simon Pilgrim
Date: 2022-08-15T17:57:34+01:00
New Revision: e471fdad7c32bde914dce070ec2b973e718bc40d

URL: https://github.com/llvm/llvm-project/commit/e471fdad7c32bde914dce070ec2b973e718bc40d
DIFF: https://github.com/llvm/llvm-project/commit/e471fdad7c32bde914dce070ec2b973e718bc40d.diff

LOG: [InstCombine] known-phi-br.ll - add multiuse of compare results to avoid predicate inverse and add negative tests

Feedback from D131838

Added: 
    

Modified: 
    llvm/test/Transforms/InstCombine/known-phi-br.ll

Removed: 
    


################################################################################
diff  --git a/llvm/test/Transforms/InstCombine/known-phi-br.ll b/llvm/test/Transforms/InstCombine/known-phi-br.ll
index e0dbf84919c0..395a5299a686 100644
--- a/llvm/test/Transforms/InstCombine/known-phi-br.ll
+++ b/llvm/test/Transforms/InstCombine/known-phi-br.ll
@@ -6,11 +6,14 @@
 ; the known bits of a phi edge based off a conditional branch feeding the phi.
 ;
 
+declare void @use(i1)
+
 ; TODO: %x either eq 7 or is set to 7
 define i64 @limit_i64_eq_7(i64 %x) {
 ; CHECK-LABEL: @limit_i64_eq_7(
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i64 [[X:%.*]], 7
+; CHECK-NEXT:    call void @use(i1 [[CMP]])
 ; CHECK-NEXT:    br i1 [[CMP]], label [[END:%.*]], label [[BODY:%.*]]
 ; CHECK:       body:
 ; CHECK-NEXT:    br label [[END]]
@@ -20,6 +23,7 @@ define i64 @limit_i64_eq_7(i64 %x) {
 ;
 entry:
   %cmp = icmp eq i64 %x, 7
+  call void @use(i1 %cmp)
   br i1 %cmp, label %end, label %body
 body:
   br label %end
@@ -32,8 +36,9 @@ end:
 define i64 @limit_i64_ne_255(i64 %x) {
 ; CHECK-LABEL: @limit_i64_ne_255(
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[CMP_NOT:%.*]] = icmp eq i64 [[X:%.*]], 255
-; CHECK-NEXT:    br i1 [[CMP_NOT]], label [[END:%.*]], label [[BODY:%.*]]
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i64 [[X:%.*]], 255
+; CHECK-NEXT:    call void @use(i1 [[CMP]])
+; CHECK-NEXT:    br i1 [[CMP]], label [[BODY:%.*]], label [[END:%.*]]
 ; CHECK:       body:
 ; CHECK-NEXT:    br label [[END]]
 ; CHECK:       end:
@@ -42,6 +47,7 @@ define i64 @limit_i64_ne_255(i64 %x) {
 ;
 entry:
   %cmp = icmp ne i64 %x, 255
+  call void @use(i1 %cmp)
   br i1 %cmp, label %body, label %end
 body:
   br label %end
@@ -55,6 +61,7 @@ define i64 @limit_i64_ule_15(i64 %x) {
 ; CHECK-LABEL: @limit_i64_ule_15(
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i64 [[X:%.*]], 16
+; CHECK-NEXT:    call void @use(i1 [[CMP]])
 ; CHECK-NEXT:    br i1 [[CMP]], label [[END:%.*]], label [[BODY:%.*]]
 ; CHECK:       body:
 ; CHECK-NEXT:    [[MASK:%.*]] = and i64 [[X]], 15
@@ -66,6 +73,7 @@ define i64 @limit_i64_ule_15(i64 %x) {
 ;
 entry:
   %cmp = icmp ule i64 %x, 15
+  call void @use(i1 %cmp)
   br i1 %cmp, label %end, label %body
 body:
   %mask = and i64 %x, 15
@@ -81,6 +89,7 @@ define i64 @limit_i64_uge_8(i64 %x) {
 ; CHECK-LABEL: @limit_i64_uge_8(
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp ugt i64 [[X:%.*]], 7
+; CHECK-NEXT:    call void @use(i1 [[CMP]])
 ; CHECK-NEXT:    br i1 [[CMP]], label [[BODY:%.*]], label [[END:%.*]]
 ; CHECK:       body:
 ; CHECK-NEXT:    [[MASK:%.*]] = and i64 [[X]], 7
@@ -92,6 +101,7 @@ define i64 @limit_i64_uge_8(i64 %x) {
 ;
 entry:
   %cmp = icmp uge i64 %x, 8
+  call void @use(i1 %cmp)
   br i1 %cmp, label %body, label %end
 body:
   %mask = and i64 %x, 7
@@ -107,6 +117,7 @@ define i64 @limit_i64_ult_8(i64 %x) {
 ; CHECK-LABEL: @limit_i64_ult_8(
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i64 [[X:%.*]], 8
+; CHECK-NEXT:    call void @use(i1 [[CMP]])
 ; CHECK-NEXT:    br i1 [[CMP]], label [[END:%.*]], label [[BODY:%.*]]
 ; CHECK:       body:
 ; CHECK-NEXT:    [[MASK:%.*]] = and i64 [[X]], 7
@@ -118,6 +129,7 @@ define i64 @limit_i64_ult_8(i64 %x) {
 ;
 entry:
   %cmp = icmp ult i64 %x, 8
+  call void @use(i1 %cmp)
   br i1 %cmp, label %end, label %body
 body:
   %mask = and i64 %x, 7
@@ -133,6 +145,7 @@ define i64 @limit_i64_ugt_7(i64 %x) {
 ; CHECK-LABEL: @limit_i64_ugt_7(
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp ugt i64 [[X:%.*]], 7
+; CHECK-NEXT:    call void @use(i1 [[CMP]])
 ; CHECK-NEXT:    br i1 [[CMP]], label [[BODY:%.*]], label [[END:%.*]]
 ; CHECK:       body:
 ; CHECK-NEXT:    [[MASK:%.*]] = and i64 [[X]], 7
@@ -144,6 +157,7 @@ define i64 @limit_i64_ugt_7(i64 %x) {
 ;
 entry:
   %cmp = icmp ugt i64 %x, 7
+  call void @use(i1 %cmp)
   br i1 %cmp, label %body, label %end
 body:
   %mask = and i64 %x, 7
@@ -154,4 +168,62 @@ end:
   ret i64 %res
 }
 
+;
+; negative tests
+;
 
+; %x either ule 15 or is masked with 15
+define i64 @limit_i64_ule_15_mask3(i64 %x) {
+; CHECK-LABEL: @limit_i64_ule_15_mask3(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i64 [[X:%.*]], 16
+; CHECK-NEXT:    call void @use(i1 [[CMP]])
+; CHECK-NEXT:    br i1 [[CMP]], label [[END:%.*]], label [[BODY:%.*]]
+; CHECK:       body:
+; CHECK-NEXT:    [[MASK:%.*]] = and i64 [[X]], 15
+; CHECK-NEXT:    br label [[END]]
+; CHECK:       end:
+; CHECK-NEXT:    [[X_MASK:%.*]] = phi i64 [ [[X]], [[ENTRY:%.*]] ], [ [[MASK]], [[BODY]] ]
+; CHECK-NEXT:    [[RES:%.*]] = and i64 [[X_MASK]], 3
+; CHECK-NEXT:    ret i64 [[RES]]
+;
+entry:
+  %cmp = icmp ule i64 %x, 15
+  call void @use(i1 %cmp)
+  br i1 %cmp, label %end, label %body
+body:
+  %mask = and i64 %x, 15
+  br label %end
+end:
+  %x.mask = phi i64 [ %x, %entry ], [ %mask, %body ]
+  %res = and i64 %x.mask, 3
+  ret i64 %res
+}
+
+; %x either ult 8 or is masked with 7
+define i64 @limit_i64_ult_8_mask1(i64 %x) {
+; CHECK-LABEL: @limit_i64_ult_8_mask1(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i64 [[X:%.*]], 8
+; CHECK-NEXT:    call void @use(i1 [[CMP]])
+; CHECK-NEXT:    br i1 [[CMP]], label [[END:%.*]], label [[BODY:%.*]]
+; CHECK:       body:
+; CHECK-NEXT:    [[MASK:%.*]] = and i64 [[X]], 7
+; CHECK-NEXT:    br label [[END]]
+; CHECK:       end:
+; CHECK-NEXT:    [[X_MASK:%.*]] = phi i64 [ [[X]], [[ENTRY:%.*]] ], [ [[MASK]], [[BODY]] ]
+; CHECK-NEXT:    [[RES:%.*]] = and i64 [[X_MASK]], 1
+; CHECK-NEXT:    ret i64 [[RES]]
+;
+entry:
+  %cmp = icmp ult i64 %x, 8
+  call void @use(i1 %cmp)
+  br i1 %cmp, label %end, label %body
+body:
+  %mask = and i64 %x, 7
+  br label %end
+end:
+  %x.mask = phi i64 [ %x, %entry ], [ %mask, %body ]
+  %res = and i64 %x.mask, 1
+  ret i64 %res
+}


        


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