[Local] replaceAllDbgUsesWith: Update debug values before RAUW
The replaceAllDbgUsesWith utility helps passes preserve debug info when
replacing one value with another.
This improves upon the existing insertReplacementDbgValues API by:
- Updating debug intrinsics in-place, while preventing use-before-def of
the replacement value.
- Falling back to salvageDebugInfo when a replacement can't be made.
- Moving the responsibiliy for rewriting llvm.dbg.* DIExpressions into
common utility code.
Along with the API change, this teaches replaceAllDbgUsesWith how to
create DIExpressions for three basic integer and pointer conversions:
- The no-op conversion. Applies when the values have the same width, or
have bit-for-bit compatible pointer representations.
- Truncation. Applies when the new value is wider than the old one.
- Zero/sign extension. Applies when the new value is narrower than the
old one.
Testing:
- check-llvm, check-clang, a stage2 `-g -O3` build of clang,
regression/unit testing.
- This resolves a number of mis-sized dbg.value diagnostics from
Debugify.
Differential Revision: https://reviews.llvm.org/D48676
llvm-svn: 336451
diff --git a/llvm/test/Transforms/InstCombine/debuginfo-variables.ll b/llvm/test/Transforms/InstCombine/debuginfo-variables.ll
index 8c4aba8..50fffbf 100644
--- a/llvm/test/Transforms/InstCombine/debuginfo-variables.ll
+++ b/llvm/test/Transforms/InstCombine/debuginfo-variables.ll
@@ -1,5 +1,7 @@
; RUN: opt < %s -debugify -instcombine -S | FileCheck %s
+declare void @escape32(i32)
+
define i64 @test_sext_zext(i16 %A) {
; CHECK-LABEL: @test_sext_zext(
; CHECK-NEXT: [[C2:%.*]] = zext i16 %A to i64
@@ -10,6 +12,20 @@
ret i64 %c2
}
+define i64 @test_used_sext_zext(i16 %A) {
+; CHECK-LABEL: @test_used_sext_zext(
+; CHECK-NEXT: [[C1:%.*]] = zext i16 %A to i32
+; CHECK-NEXT: call void @llvm.dbg.value(metadata i32 [[C1]], {{.*}}, metadata !DIExpression())
+; CHECK-NEXT: [[C2:%.*]] = zext i16 %A to i64
+; CHECK-NEXT: call void @llvm.dbg.value(metadata i64 [[C2]], {{.*}}, metadata !DIExpression())
+; CHECK-NEXT: call void @escape32(i32 %c1)
+; CHECK-NEXT: ret i64 %c2, !dbg !23
+ %c1 = zext i16 %A to i32
+ %c2 = sext i32 %c1 to i64
+ call void @escape32(i32 %c1)
+ ret i64 %c2
+}
+
define void @test_or(i64 %A) {
; CHECK-LABEL: @test_or(
; CHECK-NEXT: call void @llvm.dbg.value(metadata i64 %A, {{.*}}, metadata !DIExpression(DW_OP_constu, 256, DW_OP_or, DW_OP_stack_value))