Factor out the multiply analysis code in ComputeMaskedBits and apply it to the

overflow checking multiply intrinsic as well.

Add a test for this, updating the test from grep to FileCheck.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153028 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 74 insertions, 6 deletions

diff --git a/test/Transforms/InstCombine/mul.ll b/test/Transforms/InstCombine/mul.ll
index 53a56434ae..edb530585c 100644
--- a/test/Transforms/InstCombine/mul.ll
+++ b/test/Transforms/InstCombine/mul.ll
@@ -1,116 +1,184 @@
 ; This test makes sure that mul instructions are properly eliminated.
-; RUN: opt < %s -instcombine -S | not grep mul
+; RUN: opt < %s -instcombine -S | FileCheck %s
 
 define i32 @test1(i32 %A) {
+; CHECK: @test1
         %B = mul i32 %A, 1              ; <i32> [#uses=1]
         ret i32 %B
+; CHECK: ret i32 %A
 }
 
 define i32 @test2(i32 %A) {
+; CHECK: @test2
         ; Should convert to an add instruction
         %B = mul i32 %A, 2              ; <i32> [#uses=1]
         ret i32 %B
+; CHECK: shl i32 %A, 1
 }
 
 define i32 @test3(i32 %A) {
+; CHECK: @test3
         ; This should disappear entirely
         %B = mul i32 %A, 0              ; <i32> [#uses=1]
         ret i32 %B
+; CHECK: ret i32 0
 }
 
 define double @test4(double %A) {
+; CHECK: @test4
         ; This is safe for FP
         %B = fmul double 1.000000e+00, %A                ; <double> [#uses=1]
         ret double %B
+; CHECK: ret double %A
 }
 
 define i32 @test5(i32 %A) {
+; CHECK: @test5
         %B = mul i32 %A, 8              ; <i32> [#uses=1]
         ret i32 %B
+; CHECK: shl i32 %A, 3
 }
 
 define i8 @test6(i8 %A) {
+; CHECK: @test6
         %B = mul i8 %A, 8               ; <i8> [#uses=1]
         %C = mul i8 %B, 8               ; <i8> [#uses=1]
         ret i8 %C
+; CHECK: shl i8 %A, 6
 }
 
 define i32 @test7(i32 %i) {
+; CHECK: @test7
         %tmp = mul i32 %i, -1           ; <i32> [#uses=1]
         ret i32 %tmp
+; CHECK: sub i32 0, %i
 }
 
 define i64 @test8(i64 %i) {
-       ; tmp = sub 0, %i
+; CHECK: @test8
         %j = mul i64 %i, -1             ; <i64> [#uses=1]
         ret i64 %j
+; CHECK: sub i64 0, %i
 }
 
 define i32 @test9(i32 %i) {
-        ; %j = sub 0, %i
+; CHECK: @test9
         %j = mul i32 %i, -1             ; <i32> [#uses=1]
         ret i32 %j
+; CHECJ: sub i32 0, %i
 }
 
 define i32 @test10(i32 %a, i32 %b) {
+; CHECK: @test10
         %c = icmp slt i32 %a, 0         ; <i1> [#uses=1]
         %d = zext i1 %c to i32          ; <i32> [#uses=1]
        ; e = b & (a >> 31)
         %e = mul i32 %d, %b             ; <i32> [#uses=1]
         ret i32 %e
+; CHECK: [[TEST10:%.*]] = ashr i32 %a, 31
+; CHECK-NEXT: %e = and i32 [[TEST10]], %b
+; CHECK-NEXT: ret i32 %e
 }
 
 define i32 @test11(i32 %a, i32 %b) {
+; CHECK: @test11
         %c = icmp sle i32 %a, -1                ; <i1> [#uses=1]
         %d = zext i1 %c to i32          ; <i32> [#uses=1]
         ; e = b & (a >> 31)
         %e = mul i32 %d, %b             ; <i32> [#uses=1]
         ret i32 %e
+; CHECK: [[TEST11:%.*]] = ashr i32 %a, 31
+; CHECK-NEXT: %e = and i32 [[TEST11]], %b
+; CHECK-NEXT: ret i32 %e
 }
 
-define i32 @test12(i8 %a, i32 %b) {
-        %c = icmp ugt i8 %a, 127                ; <i1> [#uses=1]
+define i32 @test12(i32 %a, i32 %b) {
+; CHECK: @test12
+        %c = icmp ugt i32 %a, 2147483647                ; <i1> [#uses=1]
         %d = zext i1 %c to i32          ; <i32> [#uses=1]
-        ; e = b & (a >> 31)
         %e = mul i32 %d, %b             ; <i32> [#uses=1]
         ret i32 %e
+; CHECK: [[TEST12:%.*]] = ashr i32 %a, 31
+; CHECK-NEXT: %e = and i32 [[TEST12]], %b
+; CHECK-NEXT: ret i32 %e
+
 }
 
 ; PR2642
 define internal void @test13(<4 x float>*) {
+; CHECK: @test13
 	load <4 x float>* %0, align 1
 	fmul <4 x float> %2, < float 1.000000e+00, float 1.000000e+00, float 1.000000e+00, float 1.000000e+00 >
 	store <4 x float> %3, <4 x float>* %0, align 1
 	ret void
+; CHECK-NEXT: ret void
 }
 
 define <16 x i8> @test14(<16 x i8> %a) {
+; CHECK: @test14
         %b = mul <16 x i8> %a, zeroinitializer
         ret <16 x i8> %b
+; CHECK-NEXT: ret <16 x i8> zeroinitializer
 }
 
 ; rdar://7293527
 define i32 @test15(i32 %A, i32 %B) {
+; CHECK: @test15
 entry:
   %shl = shl i32 1, %B
   %m = mul i32 %shl, %A
   ret i32 %m
+; CHECK: shl i32 %A, %B
 }
 
 ; X * Y (when Y is 0 or 1) --> x & (0-Y)
 define i32 @test16(i32 %b, i1 %c) {
+; CHECK: @test16
         %d = zext i1 %c to i32          ; <i32> [#uses=1]
         ; e = b & (a >> 31)
         %e = mul i32 %d, %b             ; <i32> [#uses=1]
         ret i32 %e
+; CHECK: [[TEST16:%.*]] = sext i1 %c to i32
+; CHECK-NEXT: %e = and i32 [[TEST16]], %b
+; CHECK-NEXT: ret i32 %e
 }
 
 ; X * Y (when Y is 0 or 1) --> x & (0-Y)
 define i32 @test17(i32 %a, i32 %b) {
+; CHECK: @test17
   %a.lobit = lshr i32 %a, 31
   %e = mul i32 %a.lobit, %b
   ret i32 %e
+; CHECK: [[TEST17:%.*]] = ashr i32 %a, 31
+; CHECK-NEXT: %e = and i32 [[TEST17]], %b
+; CHECK-NEXT: ret i32 %e
+}
+
+define i32 @test18(i32 %A, i32 %B) {
+; CHECK: @test18
+  %C = and i32 %A, 1
+  %D = and i32 %B, 1
+
+  %E = mul i32 %C, %D
+  %F = and i32 %E, 16
+  ret i32 %F
+; CHECK-NEXT: ret i32 0
 }
 
+declare {i32, i1} @llvm.smul.with.overflow.i32(i32, i32)
+declare void @use(i1)
 
+define i32 @test19(i32 %A, i32 %B) {
+; CHECK: @test19
+  %C = and i32 %A, 1
+  %D = and i32 %B, 1
 
+; It would be nice if we also started proving that this doesn't overflow.
+  %E = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %C, i32 %D)
+  %F = extractvalue {i32, i1} %E, 0
+  %G = extractvalue {i32, i1} %E, 1
+  call void @use(i1 %G)
+  %H = and i32 %F, 16
+  ret i32 %H
+; CHECK: ret i32 0
+}